1. Field of the Invention
This invention relates to the field of collecting and preparing cervical smears for diagnostic purposes, and, more particularly, to an improved device for simultaneously collecting samples of both exocervical and endocervical cells.
2. Description of the Relevant Prior Art
U.S. Pat. No. 5,022,408, the disclosure of which is hereby incorporated by reference, describes in some detail the problems encountered with prior art cervical sampling devices. These problems include inadequacy of smear samples due to the absence of endocervical cells, excess mucous in the samples, failure to penetrate the depth of the endocervix, removal of immature cells from deeper layers of cervical tissue ("the brush effect"), abrasion of the endocervical wall which causes undesirable bleeding and obscure cervical samples, and the necessity of using two separate devices to obtain endo- and exocervical samples.
The '408 patent disclosed and claimed a combination exo-endocervical sampler. The sampler includes an elongated handle portion defining a longitudinal axis and having a free end. A row of flexible flags is disposed proximate the end of the handle portion opposite the free end. The flags are disposed at an acute angle with respect to the handle portion. A substantially longer, relatively rigid stop or filament is disposed on the handle portion proximate the row of flags. The filament serves as a stop when the device is inserted into the cervical os, and also scrapes the exocervical wall when the device is rotated 360 degrees. Rotation of the device also causes the row of flags to engage the surface of the endocervix. Therefore, when the device is removed from the cervical canal, two separated cell samples are obtained.
The sampler of the '408 patent is used to best advantage in preparing a cervical cell sample on a two-tiered microscope slide, such as that disclosed in FIG. 4 thereof. The sampler is simply wiped across the two-tier slide, thus depositing endocervical cells on the upper surface 46 thereof, and exocervical cells on the lower surface 48 thereof.
In clinical trials, the sampler of the '408 patent has shown a consistency in obtaining accurate cervical samples not attainable with the prior art. In a clinical trial involving over 300 samples obtained with the patented sampler, 99% accuracy was attained, with almost no false positive or false negative samples. Furthermore, the patented sampler does not cause bleeding, is relatively comfortable for the patient, is efficient and easy to use, and can be easily and cheaply manufactured by simple molding techniques.
However, clinical experience has shown that certain improvements to the basic patented device make it even easier and more efficient to use, particularly by medical personnel who do not have highly developed sampling skills. Thus, a need exists for an improved device which incorporates various features which improve the reliability of the sample obtained.